53 



GAMETOPHYTE OF ANGIOSPERMS 



only one of which is usually capable of being fertilized, and that 

 the antipodal cells are a remnant of the numerous vegetative cells 

 of the gametophyte. The peculiar formation of the endosperm 

 nucleus through the fusion of the two polar cells is looked upon 



Fig. 271. Section of a megasporangium of lily, showing the mature 

 female gametophyte : 5, female gamete, below which are two synergids ; 

 p, the two polar nuclei uniting to form the endosperm nucleus ; a, anti- 

 podal cells; mi, micropyle ; i, integuments; f, funiculus in which a vascular 

 bundle, v, has been formed to transport foods to the sporangium. 



as a nourishing device to give the endosperm nucleus the power 

 to grow and form a tissue that supplements the antipodal cells 

 and so takes the place of the nourishing gametophyte of the 

 gymnosperms. According to this view, the completion of the 

 gametophyte in the angiosperms is delayed until the fertilization 

 is effected. However, the origin and behavior of the various 



